Common Cocklebur
Seedling. Key characteristics: bur may be attached; cotyledons are thick and fleshy; base of hypocotyl purple-colored.
Seedling. Key characteristics: first true leaves are opposite, later leaves are alternate; leaves have three distinct veins.
Stem. Key characteristics: rough-textured with purple spots.
Vegetative plants. Key characteristics: leaves have very coarse "sand paper" texture, often lobed, coarse teeth along the margins, and long petioles.
Fruit. Key characteristics: sharp spines; each bur contains two seed.
Seed.
Life cycle: summer annual.